/**
 *    Copyright 2009-2015 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package com.yinsin.jpabatis.executor;

import java.lang.reflect.Array;
import java.util.List;

import com.yinsin.jpabatis.config.Configuration;
import com.yinsin.jpabatis.reflection.MetaObject;
import com.yinsin.jpabatis.reflection.factory.ObjectFactory;

/**
 * @author Andrew Gustafson
 */
public class ResultExtractor {
	private final Configuration configuration;
	private final ObjectFactory objectFactory;

	public ResultExtractor(Configuration configuration, ObjectFactory objectFactory) {
		this.configuration = configuration;
		this.objectFactory = objectFactory;
	}

	public Object extractObjectFromList(List<Object> list, Class<?> targetType) {
		Object value = null;
		if (targetType != null && targetType.isAssignableFrom(list.getClass())) {
			value = list;
		} else if (targetType != null && objectFactory.isCollection(targetType)) {
			value = objectFactory.create(targetType);
			MetaObject metaObject = configuration.newMetaObject(value);
			metaObject.addAll(list);
		} else if (targetType != null && targetType.isArray()) {
			Class<?> arrayComponentType = targetType.getComponentType();
			Object array = Array.newInstance(arrayComponentType, list.size());
			if (arrayComponentType.isPrimitive()) {
				for (int i = 0; i < list.size(); i++) {
					Array.set(array, i, list.get(i));
				}
				value = array;
			} else {
				value = list.toArray((Object[]) array);
			}
		} else {
			if (list != null && list.size() > 1) {
				throw new ExecutorException("Statement returned more than one row, where no more than one was expected.");
			} else if (list != null && list.size() == 1) {
				value = list.get(0);
			}
		}
		return value;
	}
}
